1. Field
The disclosed aspects relate generally to communications between devices and specifically to methods and systems for improving mechanisms for partitioning logical link control protocol (LLCP) symmetry procedure responsibilities between a Near Field Communication (NFC) controller (NFCC) a device host (DH).
2. Background
Advances in technology have resulted in smaller and more powerful personal computing devices. For example, there currently exist a variety of portable personal computing devices, including wireless computing devices, such as portable wireless telephones, personal digital assistants (PDAs) and paging devices that are each small, lightweight, and can be easily carried by users. More specifically, the portable wireless telephones, for example, further include cellular telephones that communicate voice and data packets over wireless networks. Many such cellular telephones are manufactured with ever increasing computing capabilities, and as such, are becoming tantamount to small personal computers and hand-held PDAs. Further, such devices are enabling communications using a variety of frequencies and applicable coverage areas, such as cellular communications, wireless local area network (WLAN) communications, NFC, etc.
When NFC is implemented, a NFC enabled device may initially detect a NFC tag and/or target device. Thereafter, communications between NFC devices may use a NFC-data exchange protocol (DEP). Existing specifications by the NFC Forum allow for communications to occur symmetrically between devices using a link layer called LLCP. The present NCI specification requires all of the LLCP functionality to be provided by the DH.
At present, LLCP allows multiple applications to share access to the NFC radio connection to a remote NFC endpoint. One feature of the LLCP is the concept of a symmetry procedure which effectively makes the asymmetric RF link appear symmetric to the applications. The LLCP allows for each device to send a packet within a given timeout interval, and provides a special packet (e.g., SYMM protocol data unit (PDU)) that may be sent if there is no application data (e.g., PDU) to be communicated at that time. As such, the remote NFC endpoint may have the opportunity to send a payload as a “response” in the reverse direction to a SYMM PDU.
Implementation of the LLCP through the DH is costly in terms of power consumption. For example, a NFCC wakes up the DH every time a symmetry packet is received, and the timing precision at which the symmetry packet can be sent is limited by uncertainties in interrupt latency. Features associated with LLCP such as frame aggregation and disaggregation, service discovery, connection oriented link management (including sliding window buffering) use a large amount of memory and would be very costly to implement these functions on a NFC Controller.
Thus, improved apparatuses and methods providing mechanisms for partitioning LLCP responsibilities between the NFCC and DH may be desired.